Peristalsis within a gastro-intestinal (GI) tract may transport swallowed food and may aid in digestion and eventual evacuation. Peristalsis may result in pressure waves or contractions moving along the GI tract, thereby resulting in motility of a bolus or other object within the GI tract. The bolus may include an in-vivo imaging device able to acquire and transmit images of, for example, the GI tract while the in-vivo imaging device passes through the GI lumen.
Certain pathological conditions may alter the normal motility within the GI tract. Lower than average motility may be caused by, for example, an obstruction, a blockage, or other pathological condition. Motility disorders may be caused by, for example, nervous disorders, and may not necessarily be easily visible. For example, intestinal disorders such as irritable bowel syndrome (IBS) have been linked to irregular contraction rates. For example, faster than average colon contractions rates are common in people with diarrhea-predominant IBS (IBS-D) and slower than average colon contractions rates are common in people with constipation-predominant IBS (IBS-C). Accordingly, a patient's contraction rate may be useful in diagnosing such intestinal disorders.
Some systems may compare a captured image sequence with a template sequence known to exhibit pathological behavior such as irregular contractions. A sequence match may indicate the likely presence of the pathological behavior in the captured sequence.
However, sequence comparison may be difficult for images captured by an autonomous wireless imaging devices, which typically passes through the body by natural peristalsis at unpredictable and often irregular speeds. With such irregular motion, the captured sequence and the template contraction sequence may be out-of-synch. For example, an opening of a contraction in one sequence may have the same play time or frame number as a closing of a contraction in another sequence. Accordingly, it may be difficult to automatically compare the misaligned frames in the sequences.
It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions and/or aspect ratio of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements throughout the serial views.